Concentrating an MH370 sonics search within the immediate area of a few pinger detections was overly optimistic and seems to have disregarded the characteristics of sound in deep water.
Add in the Raytheon claimed discrepancy and it's still a much larger and indefinite search area than those you see on the AMSA/JACC charts. I guess we will see whether this will be reflected in the next phase search zone prognostications.
An important factor differentiating submarine sound propagation from ULB ping propagation is attenuation of the signal. At low frequencies used for submarine detection, there is virtually no attenuation. Signal decrease is due only to distance (r-squared law) and that can be significantly lessened by focusing effects.
At the 33.5kHz frequency of the assumed pinger detection, the ocean absorbs sound at a rate of about 4.5 dB per kM. This is in addition to r-squared loss. This substantially limits detection range, and is no doubt why the original search area was small. It also leads me to believe that, if the original pinger detect was valid (and I've yet to see another explanation for the signals), the wreckage should still be found close to the detect locations.
It will be interesting to see what the reviewers have to say about this, if any is made public.
See this attenuation calculator:
Calculation of absorption of sound in seawater